[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150539
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Wed Dec 14 2022

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0530 UTC.

...SPECIAL FEATURES...

Central Atlantic Gale Warning: A large and powerful low pressure
system centered north of the area will bring strong to near
gale force W winds tonight through Thu night to the waters east
of 65W and north of 27N. Very large seas can be expected in this
area. By Thu night, the forecast calls for W to NW winds of 30-
35 kt N of 30N between 47W and 54W with seas of 17-24 ft in NW
swell. Please read the latest High Seas Forecast issued by the
National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Sierra Leone near
09N13W to 07N18W. The ITCZ continues from 07N18W to 04N35W to
03N50W. Scattered moderate convection is noted north of the ITCZ
from 04N to 07N between 36W and 46W.

GULF OF MEXICO...

As of 0300 UTC, a cold front enters the Gulf of Mexico near
Mobile Bay, AL, and extends SW to 25N92W and to the offshore
waters south of Tampico, Mexico. A squall line is about 40 nm
ahead of the cold front bringing severe weather to the coastal
waters of Alabama and the Florida panhandle tonight. Gusts will
likely exceed 35 kts in the strongest thunderstorms. Recent
observations indicate strong NW winds behind the front, where
seas have built to 10 ft. Ahead of the front, winds have
increased to near gale southerly winds, and seas have built to 6
to 9 ft. Elsewhere, gentle to moderate winds are over the far NW
and SW, as well as in the FL Straits.

For the forecast, the cold front will reach from Apalachicola,
FL to the central Bay of Campeche early Thu and from near
Sarasota, FL to the central Bay of Campeche Thu night before
slowing down and weakening. A line of strong to severe
thunderstorms just out ahead of the front will race E across the
north-central and NE Gulf tonight through Thu. Fresh to strong
NW to N winds west of the front will diminish to moderate to
fresh speeds overnight into Thu for the central and eastern
Gulf. Fresh to strong southerly winds ahead of the front will
diminish Thu as the front approaches Fl. The front should become
stationary Fri night from the Straits of Florida to the
south-central Gulf of Mexico before weakening further and should
remain in about the same position through Sat as a surface
trough forms over the SW Gulf. The gradient between this surface
trough and high pressure over the southern U.S. is likely to
induce a large area of fresh to strong N to NE winds over the
central Gulf this weekend. The trough will transition to a warm
front on Sun and lift northward to the NW Gulf by late Mon.

CARIBBEAN SEA...

Satellite derived wind data provided observations of fresh to
strong trade winds over the south-central Caribbean, mainly
south of 16N between 68W and 78W, where seas are up to 7 ft.
Moderate to fresh winds prevail elsewhere with 3 to 5 ft seas
except up to 6-7 ft in the NE Caribbean passages due to NE swell
from the Atlantic.

For the forecast, high pressure over the western Atlantic will
maintain fresh to strong trade winds across the central
Caribbean Sea through Fri, with moderate to fresh winds
elsewhere. Large long-period N to NE swell will continue to
propagate through the NE Caribbean passages and affect the
Tropical N Atlantic waters through Fri. Another large set of N
swell is forecast to propagate through the Tropical N
Atlantic waters starting late on Fri and continue through Mon
night.

ATLANTIC OCEAN...

See the Special Features section above for details on a Gale
Warning in the central Atlantic.

A stationary boundary stretches from the central subtropical
Atlantic near 31N46W and continues SW to near 25N60W, then
dissipates to the southern Bahamas as high pressure is building
in. No significant convection is associated with this boundary.
Satellite derived wind data provided observations of gentle W
flow behind the boundary to 30N. An area of moderate to fresh SW
winds is noted from 27N to 31N between 36W and 50W. Seas
surrounding the front are still generally 8 to 11 ft. A 1021 mb
high pressure center in the W Atlantic is supporting light to
gentle anticyclonic flow east of 75W and moderate to fresh SE
winds west of 75W. Seas remain up to 6 to 9 ft in NE swell.

Elsewhere, a diffluent pattern aloft is helping to induce
convection from 20N to 30N between 45W and 50W. High pressure,
near 30N28W dominates the eastern Atlantic and is supporting
gentle to moderate east winds mainly south of 25N to 20N, and
W-SW winds north of 25N. The pressure radiant between this
higher pressure and lower pressure near the ITCZ is generating
moderate to fresh trades across the Atlantic, mainly south of
20N. A dissipating frontal boundary is producing strong to near
gale force SW-W winds and rough or very rough seas near the
coast of Morocco.

For the forecast west of 55W, large long-period N to NE swell
will continue to affect much of the area for the next couple of
days. A large and powerful low pressure system north of the area
will bring strong to near gale force W winds and very large seas
tonight through Thu night to the waters E of 65W and north of
27N. Fresh to strong southerly winds are offshore NE Florida
associated with a  strong cold front that approaches the SE U.S.
coast. The front will move off the coast Thu afternoon, reach
from near 31N65W tothe Florida Keys early Sat, and merge with a
reinforcing cold front on Sun. The merged front is forecast to
reach from near 29N55W to 26N66W and then stall to the central
Bahamas by late Mon. Fresh to strong southerly winds will shift
eastward across the northern and central waters through Sat and
exit the area late Sat. Fresh northwest to north winds will
follow behind the merged front.

$$
Mora
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